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Biomedical subjects

G Masotti

Publications and source records attributed to G Masotti.

At least 73 records · Page 4Linked to original sources
PubMed1986

Treatment of hypertensive emergencies: classic and newer approaches.

Serious complications of treatment in hypertensive crises have been reported for nearly all drugs, so that testing of further antihypertensive drugs in the management of hypertensive emergencies is desirable. In the present study, the clinical efficacy and effects on cardiac function of intravenously infused clonidine were tested in 20 hypertensives with severely elevated blood pressure (diastolic blood pressure over 130 mm Hg). In all patients, the normalization of blood pressure was achieved together with a reduction in total and peripheral vascular resistance. Heart rate showed a slight and brief decrease. Cardiac performance (determined by radionuclide angiocardiography) was improved as indicated by the significant increase in ejection fraction and decrease in both end-diastolic and end-systolic volumes. The dosage of clonidine was progressively increased until a normal blood pressure (mean blood pressure less than or equal to 105 mm Hg) was obtained. The total mean dose required for control of blood pressure was 403 +/- 97.8 micrograms, administered over a mean period of 32 +/- 5.9 min. Side effects, represented by dry mouth and drowsiness, were well tolerated and of short duration. It is concluded that clonidine is an effective and safe alternative in the treatment of hypertensive emergencies.

Adult↗
PubMed1985

Pentoxifylline treatment in patients with occlusive peripheral arterial disease. Circulatory changes and effects on prostaglandin synthesis.

Pentoxifylline has recently been reported to stimulate in vitro the synthesis of prostacyclin. However it is not known so far whether the drug is able to stimulate prostacyclin synthesis in man also in vivo. In the present study the effects of pentoxifylline on prostaglandin synthesis and several circulatory parameters were studied in 10 controls and 10 patients with occlusive arterial disease after acute i.v. and medium term oral treatment. Prostacyclin (as 6-keto-PGF1 alpha) and PGE2 plasma concentrations have been measured together with arterial blood flow, peripheral vascular resistance, platelet aggregation and red blood cell deformability. Pentoxifylline was found both in healthy subjects and patients to significantly increase prostacyclin plasma concentration after i.v. treatment. In medium term oral treatment prostacyclin concentration was found to increase only two hours after administration and not 8 hours after. No significant variations in PGE2 plasma concentration were found at any time in both groups. Pentoxifylline significantly enhanced resting and post-ischemic blood flow of the lower limbs and simultaneously decreased peripheral vascular resistance both in healthy subjects and patients. Different grades of delayed platelet aggregation and increased red blood cell deformability were also observed. In conclusion results of the present placebo controlled study show that pentoxifylline increases arterial blood flow in patients with occlusive arterial disease. Moreover pentoxifylline induces a temporary stimulation of prostacyclin synthesis which can be suggested to contribute to the clinical activity of the drug as far as an antithrombotic effect in terms of inhibition of platelet aggregation is concerned.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Changes in cardiac function after effective treatment of hypertensive emergencies with i.v. clonidine.

Clonidine administration by i.v. infusion in 12 patients with hypertension emergencies (diastolic blood pressure over 130 mmHg) resulted in the normalization of blood pressure (BP) in all patients. Lowering of BP was associated with a reduction in total and lower limb vascular resistance. Heart rate showed a slight and brief decrease. Cardiac performance (determined by radionuclide angiocardiography) was improved as indicated by the significant increase of ejection fraction and decrease of both end-diastolic and end-systolic volumes. The dosage of clonidine was progressively increased until a normal BP (mean BP less than or equal to 105 mmHg) was obtained. In all patients a normal BP was achieved and in none was an initial hypertension effect observed. The total mean dose required for control of BP was 382.5 +/- 98.3 micrograms, administered over a mean period of 26.5 +/- 4.6 min. Side-effects, represented by dry mouth and drowsiness, were well tolerated and of short duration. It is concluded that clonidine is an effective and safe alternative in the treatment of hypertensive emergencies.

Adult↗
PubMed1984

Efficacy of mexiletine in the medium-term treatment of ventricular arrhythmias. A randomized, double-blind, crossover trial against placebo in ambulatory patients.

A double-blind, crossover study was designed to compare the safety and efficacy of mexiletine with that of placebo in reducing premature ventricular complexes (PVC) in ambulatory patients and to find out the dose which gives a good therapeutic response with a minimal incidence of side-effects. Twenty-six patients, who had on average 427.9 PVCs/hour, were admitted to the study. The doses given were designed to reduce the frequency of PVCs by 50% or more from the baseline value. Two out of the twenty-six patients stopped treatment because of major side-effects. In the remaining twenty-four patients the 3 weeks of treatment with mexiletine significantly reduced the rate of PVCs by comparison with placebo (-63.8% versus +7.5%). In the nineteen responders (per cent reduction of PVCs over 50%) the dose of mexiletine was 600 mg daily (200 mg every 8 hours). In the non-responders plasma levels of mexiletine proved to be in the therapeutic range, not in any way different from responders. The most frequent side-effects were digestive difficulties (fifteen patients taking mexiletine and six taking placebo). These results show that mexiletine is an effective anti-arrhythmic drug in the management of ventricular arrhythmias occurring in ambulatory patients. In the majority of patients mexiletine was found to be effective even at the lowest dose studied of 600 mg/day.

Adult↗
PubMed1984

A study of the antihypertensive effect and some pharmacodynamic aspects of nifedipine in medium-term treatment.

The antihypertensive activity of nifedipine in medium-term treatment has been studied in 30 patients affected by II and III WHO grade essential hypertension. After a 6-day period of placebo, patients were randomly allotted to group A (treated with single 10-mg doses of nifedipine) and group B (treated with single 20-mg doses). Treatment with nifedipine continued for 18 days. Patients in both groups were given one daily dose during the first 6 days, two daily doses in the following 6 days and three daily doses in the last 6 days. 1. Antihypertensive effect: In both groups, only three daily doses gave a satisfactory 24-hour antihypertensive activity. Nifedipine as monotherapy administered in single doses of both 10 mg (group A) and 20 mg (group B) normalized blood pressure (BP) and the measured antihypertensive effect was not statistically different in the two groups. The antihypertensive effect lasted between 7 and 8 hours after drug administration (both doses) and did not diminish with increasing duration of treatment or number of daily doses. 2. Change in heart rate: Nifedipine induced an increase in HR which diminished with shortening of the time interval between daily administrations. The effect on HR was unaltered throughout the whole experimental period. 3. Side-effects: Nifedipine did not induce orthostatic hypotension in any patient. Eleven of the 30 patients complained of side-effects, the most common being headache and palpitations. Incidence and severity of side-effects were not correlated with dose, whereas duration was longer with 20 mg. Side-effects never necessitated withdrawal of the drug.

Adolescent↗
PubMed1983

Role of PGE2 in the modulation of the adrenergic response in man.

The influence of sympathetic stimulation (SS) (achieved by 2 min cold application) on the plasma concentration of PGE2, PGF2 alpha (radioimmunoassay), noradrenaline (NA) and adrenaline (A) (radioenzymatic assay) and on forearm vascular resistance (indirect measurement, FVR) was studied in 16 healthy volunteers before and after cyclooxygenase inhibition by indomethacin (200 mg per day orally for 3 days) and lysine acetylsalicylate (corresponding to 10 mg X kg-1 of acetylsalicylic acid -ASA- iv). SS induced a sharp increase in PGE2 (from 8.1 +/- 4.3 pg X ml-1 before SS to 23.9 +/- 6.5, P less than 0.001 2 min after the beginning of SS and then to 18.9 +/- 10.2, P less than 0.001 to 8.4 +/- 3.9, NS, 4 and 12 min respectively after the beginning of SS). Plasma levels of PGF2 alpha remained undetectable both before and after SS. The increase in PGE2 was associated with a simultaneous increase in NA (from 13.4 +/- 24.2 to 204.1 +/- 67.2 pg X ml-1, P less than 0.001 during SS and 140.6 +/- 39.5, NS at the end of the experiment), whereas A did not vary significantly. FVR increased significantly only during SS. ASA did not affect PGE2 and NA plasma levels at rest or after SS. No PGE2 was detected during IND administration either before or after SS. IND significantly increased NA plasma concentration at the observation made 12 min after the beginning of SS (185.2 +/- 64.3 pg X ml-1 vs basal values of 135.9 +/- 46.2 pg X ml-1, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Phonometric study of the second heart sound in normal man.

The fast Fourier transform (FFT) was employed to analyze the frequency spectra of the second heart sound in 19 healthy subjects. The data obtained show that the second heart sound is mainly composed of low-frequency vibrations, and that the frequency vs. amplitude spectra for the various filters do not exceed 150 Hz. The different spectra obtained can represent a useful reference to compare with pathological acoustical findings.

Adult↗
PubMed1982

Reduced prostacyclin production in patients with different manifestations of ischemic heart disease.

Prostacyclin, a substance produced by vessel wall, has a sustained vasodilating and platelet antiaggregating activity and therefore the variations in its production in patients with ischemic heart disease are of interest. Prostacyclin production was assessed in 59 patients with ischemic heart disease and 59 control subjects matched for age, sex, body weight, smoking habits, blood pressure and serum cholesterol levels. Of the 59 patients examined, 23 had had a myocardial infarction 3 to 12 months earlier; 21 had had spontaneous angina and 15 effort angina for at least 3 months. Patients with myocardial infarction and spontaneous angina were also classified in subgroups with and without acute coronary insufficiency, according to the occurrence of ischemic attacks in the week preceding the study. Both circulating prostacyclin levels and prostacyclin produced after 3 minutes of ischemia were measured by bioassay. Circulating prostacyclin was significantly less in patients with ischemic heart disease than in matched control subjects independent of the clinical type of ischemic heart disease. Circulating prostacyclin was particularly reduced in patients with acute coronary insufficiency in comparison to patients without, both in the group with myocardial infarction (1.11 +/- 0.22 ng/ml and 2.09 +/- 1.32, respectively) and in the group with spontaneous angina (1.24 +/- 0.42 and 2.17 +/- 1.16, respectively). No differences could be found for prostacyclin produced after 3 minutes of ischemia in relation to the presence of acute coronary insufficiency. The lower level of prostacyclin production in patients with ischemic heart disease and especially in those with acute coronary insufficiency may be an important factor in the occurrence of coronary occlusion or spasm.

Adult↗
PubMed1982

Phonometric study of the human first heart sound.

The first heart sound was studied in 20 normal subjects. The phonocardiogram (PCG) was recorded from apical and mid-precordial areas using microphone with a flat response curve from 0.2 to 8,000 Hz. It was stored, together with a simultaneous electrocardiogram, on an FM analog tape recorder (linear frequency response from 0 to 4,000 Hz), fitted with a filter with weighting curve B according to the American National Standard Institute. A linear (SPL) recording was also made. The signal was fed through a digital converter into a minicomputer and the frequency distribution of the first heart sound was analyzed using Fast Fourier Transform. These data were stored and the average spectra were calculated for both B and SPL. The SPL spectra from both apex and mid-precordium showed a maximum intensity of about 80 dB between 12-20 Hz, decreasing progressively to a constant level of 35 dB between 110-120 Hz. The spectra obtained from both areas using filter B showed a maximum intensity of 40-50 dB between 20-60 thereafter. It is important to emphasize that the dB values in B and SPL are absolute, since they refer to a standard reference weighting. It appears that the SPL recording is more valuable in that it allows the study of all components of the PCG signal. The spectra obtained in this study will be used as a standard for future research in various pathological conditions.

Adolescent↗